Control for tilting seat and back of posture chairs



Ma'ch 12, 1957 G, A, SQDERBERG. 2,784976? CONTROL FOR TILTING SEAT AND'BACK OF' -PSTURE CHAIRS 2 Sheets-Sheet l Filed April 28, 1955 INVENTOR)ZQ'QLM ATTORNEYS March A2, 1957 G. A. SODERBERG @gdwm? CONTROL FORTILTING SEAT ND BACK OF POSTURE CHAIRS /9 9g INVENTOR ATTORNEYS.

United States Patent O CONTROL FOR TILTING SEA'IYALND BACK. 0F POSTURECHAIRS Gusta Ar.` Soderberg, Bridgeport,` Conn., assigner, by

dii'ect-` andmesne assignments, of thirty-three and onethird1 percent toH. Manton Ahlherg and` thirty-three andone-third percent tot SiegfriedJ. Ulimann, Stratford', Conn.

Application April 28, 1955,.SerialiNo. 504,477

9 Claims. Cl. 155-77) Thisy invention relates to` a control or iron foroffice chairs, particularlyF to a` control for the tilting seat andback` of the. so-called1 posture` chairs, and` has foran object toprovide an improved construction of control for the tilting seat andback of this type of chair which will: use a torque bar formed` of aheatftreated steel alloy to control the action instead of the usual coilsprings or rubber cylinders.

Another object is` to provide a construction which will permit the rearedge or rear part of the seat to'be lowered or tilted downwardly about apivot at or near the front edge of the seat, and the backrest may betilted backwardly without relative vertical or` up. and down movementbetween the back and the seat which would tend` to cause disarrangementor untidiness of the garments of the user ofthe chair.

It .is a further object to provide a` construction and arragement inwhich the height ofy the front edge oi the seat does not vary or changematerially during tilting movement, so that` when the back and seat aretilted backwardly the users feet can` maintain the` usual andcomfortable position on the oor. Also, although the back is pivoted` totilt on a pivot at substantially the center of the seat, it andv theseat can tilt backwardly without changing the height of the front edgelof the seat; or in other words, the rear edge of the seat can tilt` orshift downwardly with the back but the front edge of the seat remains atthe same height.

It is also an object to provide a control construction of this typewithmeans. whereby the angular position of the back rest with respect tothe seat and its height above theseat may be readily adjusted- A furtherobject is to provide simple and improved means whereby the height of thechair seat may be readily and easily adjusted,

Withv the foregoing and other objects in view, l have devised theconstruction illustrated in the accompanying drawings. forming a part ofthis specification. lt is, howeven, to be understood the inventionis notlimited to the specic details of construction and arrangement shown, butmay embody various changes and` modications within thescope` of theinvention.

In these drawings:

Fig. 1 is a top plan view of this control;

Fig, 2 is a side view looking toward. the bottom of Fisq 1;

Fig. 3 is a front view looking from the left ol` Figs. l and2;

Fig.` 4' isV aA detail section of a` portion of the support for thefront edge portion of the seat;

Fig. 5 is a side view of one of the elements ofthe support;

Fig. 6 is a side view of another element of the support;

Fig. 7 isa partial` elevation and partial vertical section of the heightadjusting means forthe chair seat;

Fig. 8V is a transverse section substantially on line of:` Fig. 7 withthe cover for the support-ing hub removed, and

ICC

Fig. 9.V is an end= view of the release looking from the right of Fig.'Z-. j

This control` device or iron for a. posture type chair comprises aibody; member 10 extending transversely from left to? rightA under theseatA shown ini dot-and-dash lines ll. Thisbody member may be oidifferent forms, but as shown` is preferably of substantially U-shapedcross section including spaced upright longitudinal side walls-.12 andl.- connected bya transverse bottom; wall 14, andl these wallsareconnected` at their opposite ends by the upright endtransversef walls`15, and atthe center the body. member has adownwardly extending lug orextension. 16. havinga.v socket lf to.- receive theupper reduced endolil the screw post 18V for supporting the chair seat and back on theusual type obase` support or feet 19. This body may` belsecured to-theupper' endofthis post by 'any suitable means, such, for.l example, asAthe transverse pin 20. The body member is provided with baclcwardlyextending arms 211 adjacentits.- opposite ends forming bumper` supports`for suitable bumpers 22 of any` suitable material, such, for example, assoft rubber, and:l located in a-propen position to engage aY part of thetiltingf support` for` the back: and. rear portion ot` the seat tolimitthe tilting movement of. these members, as will later befdescribed.

Extending longitudinally in the body member l0 betweenthe sidewalls i2and 13., and passing through openingsA i'nf the end walls l5A providinga bearing@ therefor, is a` torque bar 23. which is` preferably formed ofheattreated. alloy steel so: as to. have the required strength andresiliency to; control` the. tilting movements.` of the seat and bach,and toreturn. and maintain. them in the forward and normal positionsywhen the tilting pressure isreleased. Atits` right-,hand endll this barprojects from the ende of the body lil, and mounted on` it is` altorque` bar adjustment holder 24: secured-r to` the bar by anysuitablemeans, such asset screws 25. This holder includes aA forwardlyand downwardly. projecting arm 26A engagingL the free end ofV anadjusting, screwl 27- threaded` for adjustmentin. thesupporting lug 28on a` laterally extend ing bracketarm. 29 of thebody lil: This screw isprovidedr with. a hand. wheel. 30 tor operating it to shift the.position. of the: arm. 26ito adjust the` torsional tension in the bar26,. aswill. later be described.

Extending forwardly from` the body 10 are. right andleft front carriersk31, and 32. These: carriers areV ofinverted` U` shapein. cross` section`comprising laterally spacedi upright side. walls` 33- connected by atransverse top. wall 34, and. they are secured to body member 10adjacent the opposite endsthereot by-4 upright` forwardly extending,arms` 35` located. between the side walls 33t and secured, to them-.bysuitable means, such, for example, as

the` transverse rivets `36. Attheir forward` or free ends these carrierssupport the front spideirarm 3.7- extending across under. the. frontportion of the` seat il. fom left toA right, ande the seat` is. securedtheretov by any suitable means,` such, for example, asiscrews (snotshown) through openings tiinV this arm. This spider arm isY preferably'of channel' shape in cross. section to` secure strength and stiffness.in proportionA to the amountot` metal in it, andA it. includesy the.spaced. upright` flanges 39 connected by the. transverse. top` wall` 40,and this` top wall may be cut away or` provided withr elongated'openings 41- to reduce its weight.. This spider arm- 37 isr connectedwith the-.frontcarriersl and.3,2-so, asto` be supported thereby, byuprightA angular membersy 42` including a` tapered upright` body portion43 with a` laterally extending liorizontal ilange` 44 at, its upper`end. This flange seats: at the. under side. of the top wall 40 of thebar 37 between the flanges 39f andV is secured thereto` by' anysuitable` means-,. such,.forexample, as. the-rivets.n 45. These sup.-ports or angular members 4Z are connected one to each of the carriers 31and 32 by means of an upright link 46 pivoted adjacent its lower end tothe forward ends of the carriers 31 and 32 by a transverse pivot rivet47 passing through the side members of the carrier and the opening 48 inthis link. This thus forms a pivotal connection between this link andits supporting carrier 31 or 32, and the link is located between theside walls 33. Adjacent its upper end the links 46 are each providedwith an opening 49 by means of which this upper end of the link ispivotally connected to the member' 42 by the rivet 56 passing through anopening 5l in the upright portion 43 of this member. Adjacent its lowerend member 43 is provided with an elongated curved opening 52 struckabout the center of the opening 51 as a center. Thus the member 42 haslimited movement relative to its carrier 31 and 32 by swinging movementof the link 46 about its pivotal connection 47 to the carrier, but italso has relative longitudinal movement with respect to the carrierwhich is permitted by the elongated opening 52 through which the rivet5.57 extends. This movement is provided for a purpose presently to bedescribed.

Mounted on the projecting end portions of the torque bar 23 is means forsupporting the rear edge portion of the seat 11 and also the back restassociated therewith. This support includes a pair of laterally spacedrear chair seat holders 53 including wall 54 on which the seat rests andto which it may be secured by suitable screws in openings 55 in thiswall. This wall connects laterally spaced upright supporting walls 56and 57 preferably in the form of upright plates, the walls 56 extendingforwardly and having openings at their forward ends through which thetorque bar 23 extends and by which the plates 56 are supported on thisbar. Extending transversely between and secured to these plates 56 is atilting rear frame 58 comprising an angle member including an up rightflange 59 and a forwardly extending flange 60 at its upper edge, and atits opposite ends this frame includes forwardly extending end walls 61located at the inner sides of the plates 56 and may be secured theretoby any suitable means, such, for example, as welding. The torque bar 23also extends through openings in these end walls 61 to provide a widerbearing support for the rear frame and rear chair seat holder on thisbar. The walls 57 are provided with laterally extending flanges 62connected to the upright flange 59 of the frame 58 by any suitablemeans, such, 4for example, as welding 63.

Also mounted on the tilting rear frame 58 is a rear frame support 64comprising laterally spaced upright plates or end walls 65 and aconnecting top wall 66 resting at its front end portion on top of theflange 60 of the tilting frame member 58 and secured thereto by anysuitable means, such, for example, as welding 67. The upright end walls65 are provided with laterally extending flanges 68 at their forwardedges resting against the rear side of the upright wall or flange 59 ofthe frame member S8 and secured thereto by any suitable means such aswelding 69.

The support for the back rest (not shown) but which may be the regularor suitable support or back rest for this type of chair, is supported bythe transversely extending back plate 70 on suitable upright supportingbars 71 secured to the opposite ends of this plate. This plate andtherefore, the back, including the back rest, are mounted on the rearframe support 64 for both tilting adjustment with respect to thissupport and also ad* justment up and down for height with respect tothis supn port and the chair seat. For this purpose there is secured tothe forward side of the plate 70 a lock plate 72, this plate 72 beingsecured to the plate 70 by any suitable means, such, for example, asrivets 73. The opposite ends 74 of the plate 72 are bent or olsetforwardly so as to be spaced from the plate 70 to receive between theseplates the upright laterally extending flanges 75 of a pair of side tiltcarriers 76 which are located at the outer side of the upright wall 65and are pivotally connected thereto by the pivot studs 77 passingthrough the members 76 and the walls 65. The side tilt carriers 76 areconnected by the back plate support 78 extending between these members76 at the forward side of the offset ends 74 of the plate 72, and thisplate 78 is connected at its opposite end edges to the members 76 bylugs '79 extending through openings in the members 76 and riveted overto provide a rigid connection between them. Thus the plates 70 and 72carrying the supports 7i for the back rest may be adjusted vertically orup and down on the anges of the side tilt carriers 76, and they may belocked in adjusted position by the locking bolt 8i) passing through anupright elongated slot in the plate 7S and having a head 81 at theforward side thereof, the bolt also passing through plates 72 and 70 andthreaded into a hand Wheel 82 with a washer 83 between the inner end ofthe hub 84 of this wheel and the plate 7d. It will be clear that afteradjustment of the plates 70 and 72 the back rest may be secured inadjusted positions by tightening up the locking hand wheel 82.

The side tilt carriers 76 may be shifted to different angular' positionson the `rear frame support 64 by shifting them about the pivot 77. Theymay be secured in different angular positions by a transverse `clampingor locking bolt 85 extending through the end walls 65 of the support,and elongated curved slots S6 in the walls '76 struck about the pivot 77as a center. Side clamps 87 are also located yon the outer side of thewalls 76 on the pivots 77, and the bolt 85 extends through these clamps.At one end the bolt includes a head 88 and Aat its opposite end it isthreaded into the hub or shank of a T-handle 99. A sleeve or tube @lembraces the bolt 85 and extends between the side walls 65 of the framesupport. Thus, after adjustment, by tightening up of the T-handle 99 theclamps 87 in the walls 76 are clamped oy the bolt against the side walls65 to lock the members 76 and therefore the plate 7@ indifferent angularpositions.

To control the tilting movements of the chair seat and the back `thefree end of the torque bar 23 opposite the control 2.4 is bent laterallyas indicated at 92 at the outer side of the side wall 56 of the seatholder 53, and its free end is secured or locked thereto by the torquebar lock 93. In the form shown this comprises a hat bar secured adjacent`one endy to the plate 56 by the bolt 94 and having a looped portion 95embracing the free end of the laterally extending portion 92 of the barand having the free end of this loop extending lthrough a slot in thewall 56 and "bent downwardly on the inner side thereof to form a lockingflange 96 to securely secure and lock this member 93 as well as the freeend of the laterally bent portion 92 of the torque bar to the member 56,and therefore to the rear chair seat holder 53 and the rear framesupport 6ft carrying the back and back rest.

The seat and its support, together with the support for the back, areshown in their normal. positions in Figs. l and 2. The body member 10and the forwardly extending carriers and supports `for the front spiderarm 37 are stationary on the screw post 18, while the rear chair seat`holders 53 and the lrear frame support 64 carrying the rear edgeportion of the seat and the hack restare tiltable downwardly andbackwardly about vthe torque bar 23 as a pivot, and this downwardmovement of these members is limited by the forwardly extending flange6@ engaging the bumpers 22. Substantially theposition of the rear edgeportion of the seat 11 is indicated in Fig. 2 by the broken lines iin.During this "down ward or tilting movement the free lend `of thelaterally bent end 92 of the torque bar is swung downwardly, thusplacing a torsional strain on this bar which tends to return thesesupports 63 and 64 to their upward or normal position of Fig. 2, andtherefore of course carry with them the rear edge por-tion of the chairseat and the back. Therefore, when backward tilting pressure to thechair weaver seat' and the hack is applied by. a person. sitting, in thechai-r andl'eaning backwardly, a torsional strain is placed on thetorque bar, but as the person yleans forward or gets up from the chair,thus releasing the backwardly tilting pressure on. the seat and back,they are returned to the normal position by torsional' tension or stressin the torque bar. This stress may be adjusted by means of the screw 27acting against the `arm 26 connected to the torque bar, it beingincreased by shifting the screw 27 baekwardly or to the right `as viewedin Fig. 2. As this bar is of `considerable length and' the movement ofthe free end 92'during the tilting operation is relatively small, thereis very little, if" any, increase in. stress built up in the bar duringthe tilting movement, and therefore the stress in the bar issubstantially uniform for yall positions Iof the tilting support.

lt willlbeseen from Fig, 2 that as the rear edge portion of. the chairseat is lowered or tilted downwardly, as well as the back support tiltedrearwardly, the movement is on an arc about the center axis lof thetorque bar Z3. Thus, as indicated in Fig, 2, the rear edge, indicated bythe rear edge 97 of the. support 5d' will move on the arc 9S"struck'from the center of this bar; This will mean that this point and'therefore the4 seat during the downward tilting movement. must shift ormove bodily rearward a certain amount. Therefore, the front end spiderarm 37 must move rearwardly. ln other words, the rivet Sil on eachsupporting member 42 for the lfront'` spider arm 37' swings to the rightor rearwardly with the upper. end of the link 46 about its pivotalconnection i7 to the supporting arms 31 and 32. As the rivet 56 is fixedin the memher 42, this member must lalso shift to the right` orrearwardly as viewed in Fig. 2, and this movement is permitted by theelougatedopening of Vslot 52 embracing the lower. pivot rivet. 47 of thelinl: t6. However, the height ofthe rivet i? above the floor varies onlyvery slightly and therefore. this` movement does not vary the heightofthe `forward end edge. lill; of the chair seat above the l'oor.Therefore, with this construction the downward movement of the rear endportion of the chair orthe tilting movement of` the chair seat` and theback. is eiected without changing the height of the. forward edgeportion of the chair seat above the hoor, so that when these parts aretilted as the users feetv can lstill maintain their normalandicomfortable position on the floor. Also during'the: tiltingmovements of the chair seat and back there is no vertical or up' anddown relative movement between the rear' edge portion of the seat andthe bach which would tend to cause d-isarrangementor untidiness of thegarments `of the' user of the` chair.

An improved means for adjustingV the height ot the chair isshownLin'Figs. 7Y to 9. Any suitableor usual type ofbase or supportinglegs is employed', the top or upper portion of which is partially shownat 19 provided with4 an opening in which is' seated a tubular hub 99provided with an' enlarged hollow head portion 166 thus providing alateraiiy'extending harige or shoulder 191 seating on the top of thebase 19'. This hollow head is open at the top but is closed by a coveror closure 132 having side walls 1lb?) telescoping with the. head iti.Mounted within this tubular hub are upper. and lower bearings ldd andlilSresp'ectively'for the screw post 1h. These bearings can be atight'fit in the sleeve 99, and the upper bearing is provided with a laterallyextending hangs 1lb? at its upper end restingon the oifset 101i oftheitubular hub` Resting on the top of this ange 166, and thereforehaving a supporting thrust bearing thereon, is a nur 167 having threadedengagement with. the. screwpostl 1S, and therefore byfrotatingthis'nutthe height of the post in the base 191 maybe adjusted, or,more'correoti'y, if the nut is heid stationary and' the post 1-8- isrotated, the height of4 the chair seat may be adjusted. This nut isprovided with an outwardly extending flange d at its lower end, and thenut has a laterally extending opening 109 in one side wall in which ismounted the stop pin lll) having its free end projecting outwardly acertain distance beyond the outer wall of the nut. This pin may be adrive or force fitV in the nut; At the opposite side of the nut iti'sprovided'witli a recess 111 extending. outwardly from thethreadedopem ing through the nut, and in this recess is a steel ball 112in back of which is a spring 113 tendingto force this ball inwardly andnormally keep it seated in a longitudinally extending channel or groove114 in one side` of the screw post 1S. This spring-pressed ballcooperating with this groove or channel provides a yieldable connectionbetween the post 18 and the nut 137, which will normally cause the nutto rotate with the post unlessit is` held' stationary by some othermeans, and thus the nut will provide a supporting thrust bearing for thepost and will rotatably support the post and the chairseat with itscontrol carried thereby on the lower flange bearing' 106'and on the base19. Whilerthe'nut is free' to turn, rotationof the chair seat andtherefore the post 18 will rotate the nut and therefore permit swivel orturning movementsof the chair seat without varying the height of 'theseat.

However, means isprovided wherebythe nut may be heldstationary so thatturning movements ofthe chair and therefore the post 18 may be employedto adjust the height of the chair above the base 19, and therefore, ofcourse the iloor. For this purpose there is mounted on thebase 19 at oneside ofthe head 1100 of the tubular hub a bracket 115, in this casecomprising a strip of metal having its intermediate portion 116 bent tosubstantially inverted U shape and laterally extendingflanges forming`feet M7 resting on the top of the hat' metal ring 11'8`on top ofthe base19, and thebracltet may besecured to this ring" by any suitable meanssuch as the screws 119; Mounted in this bracket between the side walls`lIG1 is a slide 12h having itsinner end 1,'21 projecting through anopening ink the' side wall of the head` 100'. This slide is mounted forlateral in andy out movements in the bracket iii-'Sp ln the arrangementshown it is provided with a pair of elongated slots 122 through whichare transversely'extending guidek pins 12.3. Pivoted to the outer headportion of the slide 12d at 124 is a lock finger or catch' 125' having adownwardly extending'lug` 126 at its fiee end' adapted to seat in anopening-12"] in the top wall of the bracket 11S to hold the slide`1251*n in the normal position shown in Fig; 7`, which is anintermediateposition for' this slide, with its inner end 121 overlappingthe top of the flange idd on the nut 167, as shown; ln this positionthis slide cooperates with this flange to prevent' the nut 167E beinglifted off its bearing support 196; Therefore, this provides aconnection between the chairseat andthebase to prevent lifting the chairseat from the base.

The catch-125 has an overhanging finger grip 123' at its free end bywhich it may be lifted to remove the lug- 1`2from the opening lli. Thiswill release the slide12il and permit it to be shifted either inwardlyor outwardly from the position shown in Fig. 7. if it is shiftedoutwardly, or to the right as viewedin this gure, this mover ment willshift its inner end 121` away from its overhanging position with respectto the illange idd on the nut ldi'J and therefore will release it andpermit lifting. of the chair seat and the supporting control carried bythe post i8, separating them from theA base 19: If the slide 12d isshifted inwardly from the position of Fig, 7`, its inner end 121 may beshifted inwardly beyond the- 'free end of the stoppin 110; Then if thechair seat' andthe post it are rotated, this pin 11d wiliengage theinner end 121 of the slide and hold the nut lii against rotation. Thenthe spring-pressed ball 1.12 will yield and permit the chair seat andthe post. 1S to be rotated withrespectttor this. stationary held nutand. adjust thel height. of the` chair seat. either upwardly ondownwardly, as.` desired. After theY proper adjustment has been secured;shifting; of the slide 12h` back to its intermediate position willrelease the nut 107 and prevent relative turning movement between thepost and this nut, and prevent further adjustment. Slide 12?, however,being in this position, with answer its inner end overlianging thellange MP8, will prevent separation of the nut post and therefore thechair seat from the base; This provides a simple and effective means forconnecting the chair seat to the base, and one which may be readilymanipulated with a simple operation to permit adjustment of the heightof the chair seat, and then after the proper adjustment has beensecured, may be easily reset to permit swivelling or" the chair seatwithout causing height adjustment, and at the same time will secure thepost and the seat and other construction carried thereby to the base.

'Having thus set forth the nature of my invention, I claim:

l. In a chair control of the character described, an elongatedtransversely extending body member, a supporting post on which the bodyis mounted, supporting arms extending forwardly from the body, atransversely extending seat supporting spider arm at the forward ends ofsaid supporting arms, means mounting the spider arm on the supportingarms for forward and back horizontal movement as well as pivotalmovement, a longitudinally extending torque bar mounted in the bodymember, a rearwardly extending chair seat holder pivotally mounted onthe body for Vbackward tilting movement, a back rest support mounted onsaid holder, means holding one end of the torque bar stationary, theother end of the torque bar being bent laterally forming a laterallyextending arm, and means anchoring said latter arm to the rear chairseat holder to place torque stress on the bar as the holder is tiltedbackwardly.

2. In a chair control of the character described, an elongatedtransversely extending body member including upright end walls, asupport for the body, supporting arms extending forwardly from the body,a transversely extending seat supporting spider arm at the forward endsof said arms, upright links pivotally connected to said spider arm andthe supporting arms mounting the spider arm on the supporting arms forpivotal movement and horizontal back and forth movement, alongitudinally extending torque bar in the body and mounted in said endwalls, Va rearwardly extending chair seat holder pivotally mounted onsaid bar for backward tilting movement, means holding one end of thetorque bar stationary, the other end of this bar including a laterallyextending arm, and means locking lthis latter arm to the rear chair seatholder to place torque stress on the bar as the holder is tiltedbackwardly.

3. In a chair control of the character described, an elongatedtransversely extending body member, forwardly extending supporting armson the body, a chair seat above the body, pivotal means connecting thefront edge portion of the seat to said arms for back and forthhorizontalrv movement, a rearwardly extending chair seat support for therear edge portion of the seat pivotally connected to the body forrearward and downward tilting movement, and resilient means on the bodyconnected to the rearwardly extending seat support to resist saidtilting movement.

4. In a chair control of the character described, a body member, a chairseat, means mounting the forward edge portion of the seat on the bodyfor pivotal as Well as horizontal forward and backward movement, asupport for the rear edge portion `of the seat pivotally connected tothe body for up and down tilting movement, and resilient means on thebody connected to the rear seat support and resisting downward tiltingmovement of said support.

5. In a chair control of the character described, a body member, a chairseat, means mounting the forward edge portion of the seat on the bodyfor pivotal as well as horizontal forward and backward movement, asupport for the rear edge portion of the seat pivotally connected to thebody for up and down tilting movement, a longitudinally extending torquebar mounted in the body, means holding one end of the bar stationary, alaterally extending arm at the other end of the bar, and means lockingsaid arm to the rear seat support to place torque stress on the bar bydownward tilting movement of said support.

6. `In a chair control of the character described, an elongatedtransversely extending body member including upright end walls, asupport for the body, supporting arms extending forwardly from the body,a chair seat, downwardly extending support members for the front edgeportion of the seat, means pivotally connecting said supporting membersto the forward ends of said arms and permitting back and forthhorizontal movement of these members on the arms, a support for the rearedge portion of the seat pivotally mounted on and extending backwardlyfrom the body for up and down tilting movement, and yieldable resilientmeans mounted on the body and connected to said rear support to resistsaid tilting movement.

7. :ln a chair control of the character described, an elongatedtransversely extending body member including upright end walls, asupport for the body, supporting arms extending forwardly from the body,a chair seat, downwardly extending supporting members for the front edgeportion of the seat, upright links pivotally connected at their oppositeends to the supporting members and the supporting arms, a support forthe rear edge portion oi the seat pivotally mounted on and extendingbackwardly from the body for up and down tilting movement, alongitudinally extending torque bar mounted in said end walls, meansholding one end of the bar against turning, a laterally extending arm atthe other end of the bar, and means locking said arm to the rear seatsupport to place a torque stress on the bar by downward tilting movementof said support.

8. In a chair control of the character described, a transverselyextending body member, a support for the body member, supporting armsextending forwardly from the body, a chair seat, downwardly extendingsupporting members for the front edge portion of the seat, upright linkspivotally connected lat their opposite ends to said supporting membersand said arms to permit forward and backward movement of the seat, asupport for the rear edge portion of the seat pivotally mounted on andextending backwardly from the body for up and down tilting movement, andyieldable resilient means resisting said tilting movement.

9. In a chair control of the character described, a transverselyextending `body member, a support for the body member, supporting armsextending forwardly from the body, a chair seat, downwardly extendingsupporting members for the front edge portion of the seat, uprightlinks, pivot means connecting the upper ends of the links to saidsupporting members and the lower ends of said links to the supportingarms, said supporting members being provided with longitudinallyextending elongated slots embracing said lower pivot means permittingbackward movement of the seat, a support for the rear edge portion ofthe seat pivotally mounted on and extending rearwardly from the body forup and down tilting movement, and yieldable resilient means resistingdownwardly tilting movements. y

References Cited in the le of this patent UNITED STATES PATENTS1,783,426 Huntley Dec. 2, 1930 2,321,385 VHerold June. 8, 1943 2,543,924Mondy Mar. 6, 1951 2,650,646 Herold et al. Sept. 1, 1953

